Speedo works and it's correct?

[Abstrastic]

I drove the heep today on paved roads while using my phone as the digital speedometer and low and behold the speedometer in my jeep works correctly.

Now my questions go as followed:

1) axles aren't stock meaning regeared? How do I tell if this is the case?

2) speedometer gear has been changed to fit the 35's with stock gears 3.55's?

3) both of the above questions have been addressed?


I have never owned a single xj or wj that had the correct speedometer so I am bewildered.

 

[Ol Blue]

1) You can take the diff cover off and count teeth on ring and pinion. Divide # of ring teeth by # of pinion teeth for gear ratio. You can also look on the side of the ring gear and it usually has the ratio on it. Some aftermarket gears would say "373" and some would say "41 11" or "11 41". 41 is ring teeth and 11 is pinion teeth. 41/11=3.73. If you don't want to pull the diff cover, you can jack it up and count rotations. For every 1 rotation of the tire the driveshaft will turn the number of the gear ratio. If you have 4.56 gears, every 1 turn of the tire will be 4.56 turns of the driveshaft. It should be pretty apparent when driving if it has been regeared. If it feels like and absolute anemic gutless dog you probably have stock gears. If it only feels kinda like a dog it was probably regeared.

2) Here is a chart to pick speedometer gear in the transfer case. You can pull it and count teeth if you want. Only takes a few minutes. The stock tooth count would depend how the Jeep was originally configured. If the speedo reads correctly its pretty likely someone changed the speedo gear, regardless of whether the axles were regeared or not.

PPR Industries Speedometer Gear for 93-06 Jeep Vehicles

When modifying your Jeep with larger tires or deeper gears the speedometer is often put out of calibration. These pinion gears easily put the speedometer back to it's factory settings allowing you to know your correct speed and mileage.

www.quadratec.com

 

[Abstrastic]

It's definitely not gutless. I'll crawl under it Wednesday. I used my phone as a digital speedometer because I figured the speedometer was way off and it was spontaneous on.

 

[Ol Blue]

Also wanted to make an amendment to counting tire and driveshaft revolutions. Turn the tire 1 time and count the DS rotations if you have a locker or LSD (ie both tires turn the same direction when you rotate one). If the diff is open (only one tire turns) you will rotate the tire 2 full turns and count the DS rotations. If it is open, its best to leave one tire on the ground and rotate only the lifted tire 2 full turns. Again the number of DS rotations is your gear ratio.

 

[Abstrastic]

Also wanted to make an amendment to counting tire and driveshaft revolutions. Turn the tire 1 time and count the DS rotations if you have a locker or LSD (ie both tires turn the same direction when you rotate one). If the diff is open (only one tire turns) you will rotate the tire 2 full turns and count the DS rotations. If it is open, its best to leave one tire on the ground and rotate only the lifted tire 2 full turns. Again the number of DS rotations is your gear ratio.

Thinking an open diff. When at a stop and hold the brakes its spins both tires

 

[Ol Blue]

If both tires are doing a burnout its unlikely to be an open diff. That would tell me you have some kind of traction device in there. Open diffs would usually give a one wheel peel.

Maybe you should just pull the diff cover and answer all your questions at once.

 

[Abstrastic]

If both tires are doing a burnout its unlikely to be an open diff. That would tell me you have some kind of traction device in there. Open diffs would usually give a one wheel peel.

Maybe you should just pull the diff cover and answer all your questions at once.

Thats a typo meant think it's not an open diff.